1. Field of the Invention
The present invention relates to novel arylenevinylene polymers, precursor polymers suitable for use as electrodes, sensors, electronics display elements, photoelectric converting elements, non-linear optical elements, photosensitive members for electrophotography and other various electroconductive materials or optical materials in the electrical and electronic fields, and processes for the production thereof.
2. Description of the Related Art
Polymers having high y-conjugated chains have attracted much attention industrially because of their characteristics such as electroconductivity or state of transmission between a metal and semiconductor transition, and much research has been carried out. Particularly, since 1984, in addition to polythiophene, poly-p-phenylene and polyfuran, polyarylenevinylenes have attracted attention because of their higher molecular weights and excellent processability.
For example, U.S. Pat. No. 3,706,677 discloses polyphenylenevinylene, and Japanese Unexamined Patent Publications (Kokai) Nos. 61-148231, 64-79222, and 64-79223 disclose polythienylenevinylene and polyfuranylenevinylene, and processes for the production thereof. The processes for producing arylenevinylene polymers as described in these publications include eliminating the side chains from the precursor polymers having sulfonium salts, or alkoxy groups as the side chains at the ethylene group adjacent to the respective heterocyclic rings such as thiophene and furan. Usually, arylenevinylene polymers are insoluble in solvents, but these precursors are soluble in solvents, and therefore, can be easily processed and molded to form films and fibers, and can be oriented by stretching.
Furthermore, JP-A-61-148231 discloses polyarylenevinylenes having substituents and WO 88/00954 discloses polymers and copolymers of arylenevinylene having substituents. However, although the former relates to polythiophenes or the derivatives thereof having various substituents and the latter is of general extremely wide application including variety of compounds, which, at glance, seem to show the chemical structure similar to the compounds according to the present invention, there are no specifical disclosures suggesting the present compounds in the references.
The difference between benzo b!thiophene and benzo c!thiophene will now be explained. The benzo b!thiophene is chemically stable, when compared with the thiophene, and an extremely less reactive compound. Contrary to this, the benzo c!thiophene has an extremely high reactivity and can be stably present only one day even at -30.degree. C. under nitrogen. Thus, these two compounds have quite different chemical properties with respect to the reactivity thereof, although they are structural isomers with respect to the hetero atom. Please refer, in more detail, to "An Introduction to the Chemistry of Heterocyclic Compounds (Third Edition), R. M. Acheson, (John Wiley & Sons, Inc., 1976)".
In addition, the difference between polybenzo b!thiophene and polybenzo c!thiophene will be explained. The production processes and the physical properties are described, for example, in Makromol. Chem., Rapid Commun., 8, 325(1987) for the former and in J. Org. Chem., 49., 3382(1984) for the latter. For the electric properties thereof, it is reported that the energy gap(Eg) of the former is 2.9-3 eV and that of the latter is quite different and is 1.1 eV. Thus, it is known in the art that both the monomers and the polymers of benzo b!thiophene and benzo c!thiophene are quite different in the properties thereof.
Furthermore, U.S. Pat. No. 4,837,096 exemplifies arylene vinylenes having, as an aromatic ring, structures of benzo b!thiophene, benzo b!furan and benzo b!pyrrole. However, these compounds are completely different in the chemical structures thereof from the benzo c!thiophene, benzo c!furan, and benzo c!pyrrole according to the present invention. The present compounds are not specifically disclosed in this reference at all.
Nevertheless, bicyclic arylenevinylene polymers having highly .pi.-conjugated systems, such as arylenevinylene polymers having an isothianaphthene structure, were handled only as a model compound at the ab initio level by J. L. Bredas et al (SPIE Vol. 971, Nonlinear Optical Properties of Organic Materials (1988)), and nothing is known about the process for producing the above polymer. Particularly, there has been no suggestion to date that arylenevinylene polymers have isobenzofuran and isoindole structures. Isothianaphthene, isobenzofuran and isoindole, which are the starting monomers of these polymers, are unstable in air, and therefore, cannot be synthesized by the production processes used for other arylenevinylene polymers such as polythienylenevinylene, as hitherto reported.